Gabapentin Dosage

Usual Adult Dose for Epilepsy

Initial dose: 300 mg orally on day one, 300 mg orally twice a day on day two, then 300 mg orally 3 times a day on day three.
Maintenance dose: 900 to 1800 mg orally in 3 divided doses. If necessary, the dose may be increased using 300 mg or 400 mg capsules three times a day up to 1800 mg/day. Dosages up to 2400 mg/day have been well tolerated in long-term clinical studies. Doses of 3600 mg/day have also been administered to a small number of patients for a relatively short duration, and have been well tolerated. The maximum time between doses in the three times a day schedule should not exceed 12 hours.

The safety and effectiveness of gabapentin available under the trade name Gralise (R) or Horizant (R) in patients with epilepsy has not been studied.

Usual Adult Dose for Postherpetic Neuralgia

Initial dose: 300 mg orally on day one, 300 mg orally twice a day on day two, then 300 mg orally 3 times a day on day three.

The dose may be titrated up as needed for pain relief to a daily dose of 1800 mg.
Maintenance dose: 900 to 1800 mg orally in 3 divided doses.

Efficacy was demonstrated in clinical studies over a range of 1800 mg/day to 3600 mg/day. However, no additional benefit was demonstrated from the use of doses over 1800 mg/day.

Gabapentin available under the trade name Gralise (R) or Horizant (R): (Gralise (R) and Horizant (R) are not interchangeable with each other or with other gabapentin products because of differing pharmacokinetic profiles that affect the frequency of administration):

Maintenance dose: Gralise (R) should be titrated to 1800 mg orally once daily with the evening meal.

Recommended titration schedule:
Day 1: 300 mg orally with the evening meal
Day 2: 600 mg orally with the evening meal
Days 3 through 6: 900 mg orally with the evening meal
Days 7 through 10: 1200 mg orally with the evening meal
Days 11 through 14: 1500 mg orally with the evening meal
Day 15: 1800 mg orally with the evening meal

Usual Adult Dose for Restless Legs Syndrome

Gabapentin enacarbil available under the trade name Horizant (R):
600 mg orally once daily with food at about 5 PM

Usual Pediatric Dose for Epilepsy

Less than 3 years: Effectiveness has not been established.

Greater than or equal to 3 and less than 12 years:
Starting Dose: ranges from 10 to 15 mg/kg/day in 3 divided doses.
Effective Dose: reached by upward titration over a period of approximately 3 days. The effective dose of gabapentin in patients 5 years of age and older is 25 to 35 mg/kg/day and given in divided doses (three times a day). The effective dose in pediatric patients ages 3 and 4 years is 40 mg/kg/day and given in divided doses (three times a day). Gabapentin may be administered as the oral solution, capsule, or tablet, or using combinations of these formulations. Dosages up to 50 mg/kg/day have been well tolerated in a long term clinical study. The maximum time interval between doses should not exceed 12 hours.

Greater than 2 years:
Initial dose: 300 mg orally on day one, 300 mg orally twice a day on day two, then 300 mg orally 3 times a day on day three.
Maintenance dose: 900 to 1800 mg orally in 3 divided doses. If necessary, the dose may be increased using 300 mg or 400 mg capsules three times a day up to 1800 mg/day. Dosages up to 2400 mg/day have been well tolerated in long term clinical studies. Doses of 3600 mg/day have also been administered to a small number of patients for a relatively short duration, and have been well tolerated. The maximum time between doses in the three times a day schedule should not exceed 12 hours.

Renal Dose Adjustments

For patients greater than or equal to 12 years:
CrCl less than 15 mL/min: 300 mg orally every other day
CrCl 15 to 30 mL/min: 300 mg orally once a day
CrCl 30 to 60 mL/min: 300 mg orally twice a day
CrCl greater than 60 mL/min: 400 mg orally 3 times a day

The dose of gabapentin available under the trade name Gralise (R) should be adjusted in patients with reduced renal function. Patients with reduced renal function should initiate Gralise (R) at a daily dose of 300 mg. Daily dosing in patients with reduced renal function should be individualized based on tolerability and desired clinical benefit. Gralise (R) should be titrated following the schedule outlined below:
CrCl less than 30 mL/min: Gralise (R) should not be administered
CrCl 30 to 60 mL/min: 600 to 1800 mg orally with the evening meal
CrCl greater than or equal to 60 mL/min: 1800 mg orally with the evening meal

The dose of gabapentin enacarbil available under the trade name Horizant (R) should be adjusted in patients with reduced renal function:
CrCl less than 30 mL/min or on hemodialysis: Horizant (R) should not be administered
CrCl 30 to 59 mL/min: 600 mg on Day, Day 3, and every day thereafter

Liver Dose Adjustments

Data not available

Dose Adjustments

If the dose of gabapentin available under the trade name Gralise (R) is reduced, discontinued, or substituted with an alternative medication, this should be done gradually over a minimum of one week or longer or as directed by the physician.

Precautions

If gabapentin is discontinued and/or an alternate anticonvulsant medication is added to the therapy, this should be done gradually over a minimum of 1 week.

The safety and effectiveness of gabapentin available under the trade names Gralise (R) or Horizant (R) in patients with epilepsy has not been studied.

Gabapentin available under the trade names Gralise (R) or Horizant (R) are not interchangeable with each other or with other gabapentin products.

Gabapentin available under the trade name Gralise (R) should be titrated to the maintenance dose.

Gabapentin available under the trade name trade names Gralise (R) or Horizant (R) tablets should be swallowed whole, not crushed, split, or chewed.

If the dose of gabapentin available under the trade name Gralise (R) is reduced, discontinued, or substituted with an alternative medication, this should be done gradually over a minimum of one week or longer or as directed by the physician.

An antacid containing aluminum hydroxide and magnesium hydroxide reduced the bioavailability of gabapentin immediate release by about approximately 20%, but by only 5% when gabapentin was taken 2 hours after antacids. It is recommended that gabapentin available under the trade name Gralise (R) be taken at least 2 hours following antacid administration.

Safety and effectiveness of gabapentin available under the trade names Gralise (R) or Horizant (R) have not been established in pediatric patients (less than 18 years of age).

Dialysis

A 200 to 300 mg dose should be administered following hemodialysis.

Gabapentin available under the trade name Gralise (R) is contraindicated in patients receiving hemodialysis.

Gabapentin enacarbil available under the trade name Horizant (R) is contraindicated in patients receiving hemodialysis.

Other Comments

Gabapentin may be given with or without food. Gabapentin enacarbil available under the trade name Horizant (R) should be taken with food.

The first dose on day 1 may be administered at bedtime to minimize drowsiness.

Gabapentin available under the trade name Gralise (R) should be taken once daily with the evening meal.

Gabapentin enacarbil available under the trade name Horizant (R) should be swallowed whole and should not be cut, crushed, or chewed. A daily dose of 1,200 mg provided no additional benefit compared with the 600 mg dose, but caused an increase in adverse reactions. If the dose is not taken at the recommended time, the next dose should be taken the following day as prescribed.

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